Brilliant having plural rings of facets, each having an odd number of facets

ABSTRACT

A brilliant gem having upper and lower facets which are inclined to a girdle plane and formed by lateral surfaces of pyramids. The angle between the lower facets and the girdle plane ranges from 37* to 45*, and is selected such that emerging light is dispersed in a dispersion angle of from 1* 20 minutes to 12* 57 minutes. The gem is also provided with a second plane parallel to the girdle plane, and contains an odd number of upper and lower facets in a ring of facets circling the gem.

United States Patent 91 Elbe [ Jan. 29, 1974 BRILLIANT HAVING PLURAL RINGS OF FACETS, EACH HAVING AN ODD NUMBER OF FACETS [75] Inventor:

[73] Assignee: Firma Colorant Schmuckstein I G.m.b .H., Hamburg, Germany [22] Filed: Mar. 30, 1971 [21] Appl. No.: 129,421

Maximo Elbe, Hamburg, Germany [52] US. Cl. 63/32, D45/l A [51] Int. Cl. A44c 17/00 [58] Field of Search 63/32; D45/1 [56] References Cited FOREIGN PATENTS OR APPLICATIONS 573,953 3/1924 France 63/32 Primary Examiner-F. Barry Shay Attorney, Agent, or Firm-Michael Striker [57] ABSTRACT A brilliant gem having upper and lower facets which are inclined to a girdle plane and formed by lateral surfaces of pyramids. The angle between the lower facets and the girdle plane ranges from 37 to 45, and is selected such that emerging light is dispersed in a dispersion angle of from 1 20 minutes to 12 57 minutes. The gem is also provided with a second plane parallel to the girdle plane, and contains an odd number of upper and lower facets in a ring of facets circling the gem.

5 Claims, 8 Drawing Figures PATENTEUMH 29 W 3.7881397 SHEET 2 [1F 2 ln ventor MAxmo EL BE WQQALQ BRILLIANT HAVING PLURA L RINGS OF FACETS, EACH HAVING AN ODD NUMBER OF FAC'ETS This invention relates to gem stones and in particular, to brilliant gem stones having upper facets and lower facets which are inclined to a girdle plane at angles ranging from 37 to 45.

In cutting diamonds into ornamental stones according to known methods, each of the lower facets are inclined to the girdle plane, or the second plane, respectively, of the stone at an angle less than the 37 to 45 range, more specifically, the optimum range of 38.7 to 40.9". Furthermore, the lower facets are cut to define even-numbered polygons, such as octagons, hexagons, dodecagons, or multiples thereof.

These prior art cutting methods cause a light beam, entering the gem in a direction parallel to its symmetry plane and incident on a lower facet, to'be reflected by the lower facet towards another facet opposing the lower facet, and then from the second facet upwardly in a vertical direction to emerge from the stone. When this happens, no dispersion of the light beam into its spectral colors occurs, and the gems have a relatively bright appearance or brilliance, but lack or have only a weak, coloration or sparkle. Furthermore, in diamonds cut according to known methods, the dispersion of the light emerging from the gem into its various color components is almost exclusively caused by the girdle facets, which form part of the upper facets, and practically no dispersion occurs at the second plane. Brilliant gems having a second plane which is large in comparison to the surface area of the upper facets therefore show only little sparkle.

The great brilliance of known diamond gems is caused by light which falls normally onto the second plane and is totally reflected by the lower facets so that the light emerges at the top surface of the stone. The angle of emergence of a light beam, i.e., the angle between the light beam incidentupon the surface through which the beam emerges from the stone and the normal to the surface, is at most 16 in existing gems. With an angle of emergence of such a degree, the dispersion or fanout of the emerging light beam is very small, i.e., less than 1 20, and the colored light caused by the dispersion effect can hardly be resolved by the naked eye. As a result, the observer cannot distinguish the colored light and the sparkle of the stone appears weak.

The diamond and brilliant gem manufacturer desires, however, to have the greatest sparkle obtainable since the appeal of ornamental stones and particularly the appeal of brilliant gems and diamonds, is increased by the sparkle of the gem. The overall value of a brilliant stone isalso ultimately dependent upon this appeal.

According to the present invention, the number of facets in a ring of facets is an odd number and the angles between the lower facets and the girdle plane are selected such that emerging light is dispersed at a dispersion angle of 1 20' to 12 57. This design is based on a finding that a light beam entering parallel to the symmetry axis of a brilliant gem having an odd number n of corners and incident upon a lower facet of the gem ners. Thus, the light beam, upon its emergence from the stone, will be subject to a dispersion that is-substantially greater than the dispersion appearing in existing gems. For this reason, a brilliant gem made according to the present invention, has a substantially increased coloration, i.e., exhibits much more sparkle than existing stones. I

In a preferred embodiment of the invention, the number of comers is equal to l l i.e., l 1 facets are provided in a ring-like arrangement. In such a stone, the angle of emergence is much greater than the angle of emergence in existing gems having an even number of corners. The dispersion angle of a light beam emerging from the gem is dependent upon the angle B between the girdle plane and the lower facets. If B is, for example, 40, then the angle of emergence will be about 21; with an angle [3 of 45 the angle of emergence will be about 23 as compared to a maximum-angle of emergence of 16 in existing gems. The dispersion angle s will then be approximately 8, resulting in a correspondingly strong coloration. If the angle [3 between the girdle plane or the second plane respectively and the lower facets, is further increased in small increments, an angle of emergence may be reached which approximately corresponds to the critical angle of dispersion p m 23 56 of a diamond. Depending upon the degree of approach to the critical angle of dispersion, the dispersion angle e in the inventive gem may also be increased up to the maximum dispersion angle of a diamond, e 12 57.

It is apparent, that, instead of the preferred number n 1 I corners of the gem, a pyramid structure having, for example, 9 corners may likewise be selected. If, for example, the angle [3 between the girdle plane and the lower facets is 372 in a nonagon, a dispersion of the light beams emerging from the stone may be obtained which is only slightly below the maximum dispersion angle e The desired effect achieved by the invention may be further enhanced by a ring of upper facets displaced against the ring of lower facets. In a brilliant gem of this design, each main facet of the upper facets is not disposed directly above a lower facet but is staggered, i.e., arranged with its center along a line dividing a pair' of adjacent lower facets. With such a staggering of fac-. ets, a lateral deflection of a light beam falling normally on the surface of a facet results, and the desired light dispersion is thereby obtained.

It is therefore an object according to the present invention to provide a brilliant gem which is cut so as to provide a relatively high brilliancy and a strong dispersion of colored light or sparkle.

It is also an object according to the present invention to provide a brilliant gem which is simple in design, easy to manufacture, and which has substantially more coloration and sparkle than existing brilliant gems.

Other objects and features of the present invention will become apparent from the following detailed description considered in connection with the accompanying drawings which disclose several embodiments of the invention. It is to be understood, however, that the drawings are designed for the purpose of illustration only and not as a definition of the limits of the invention.

In the drawings, wherein similar reference characters denote similar elements throughout the several views:

FIG. 1 is a top view of one-half ofa brilliant gem con structed in accordance with the present invention having n l l facets wherein the upper facets are each arranged above a corresponding facet of the lower facets;

FIG. 1b is a lateral elevational view of the brilliant gem of FIG. la seen in the direction of the arrow 1b;

FIG. 1c is a second embodiment of the brilliant gem shown in FIG. la, wherein the upper facets are each displaced or staggered with respect to a corresponding lower facet;

FIG. 1d is a lateral elevational view of the brilliant gem of FIG. 1c seen in the direction of the arrow 1d;

FIG. 2a is a lateral elevational view of a gem having n 9 facets in the direction of arrow 2a of FIG. 2b showing the paths of light beams in the gem;

FIG. 2b shows a top view of the gem in the direction of arrow 2b of FIG. 2a;

FIG. 2c shows another lateral view of the gem in the direction of the arrow 26 of FIG. 2b; and

FIG. 2d is a graphic illustration showing the angle between two lower facets and a light beam incident upon and reflected by one lower facet.

Referring to FIGS. la and lb, a brilliant gem is shown having facets 1 which are located on a lower pyramid 2 which is opposed by an upper pyramid 3 having table or star facets 4 and upper girdle facets 5. Girdle plane 6 extends between the two pyramids 2 and 3 and is parallel to a second plane'7 of the gem. Lower facets l of facets l and lower pyramid 2 are cut at an angle B of 4().8 with respect to the girdle plane 6, and each lower facet l is located below a corresponding one of upper facets 8. The number n of the corners or of the facets in a ring of facets is n II.

The difference between the gem shown in FIGS. 10 and 1d and the gem shown in FIGS. 1a and lb is that each of the upper facets 8 in FIG. 1c is staggered with respect to the facets 1 of the lower pyramid 2, i.e., is displaced with respect thereto.

The advantages of the present invention may be further demonstrated by another embodiment of the invention shown in FIGS. 2a-2d which is also cut according to the concepts of the present invention. In this gem, the angle B between the girdle plane 6 and the lower facets is B 37.2. This results, due to the total reflection caused by the angles p/2, in an angle of emergence p of 23.4 and a dispersion angle 5 of about 12. Although the gem has a relatively small height and therefore correspondingly less material is required, the gem has a substantially increased sparkle because of the relatively wide dispersion of the light, as may be seen from the paths of light beams which are shown as dotted lines in FIGS. 2a-2d. Due to the angle of inclination between any two adjacent lower facets l, a light beam which enters the gem in a direction normal to the second plane is deflected at an angle p which in turn determines the angles of dispersion e.

The particular advantages of the invention reside in the fact that brilliant gems in which the angle between the girdle plane and the lower facets is from about 37 to 45, have a substantially enhanced sparkle obtained by providing an odd number n of facets in a facet ring or by an odd number of corners.

While only a few embodiments of the present invention have been shown and described, it will be obvious that many changes and modifications may be made without departing from the spirit and scope of the in vention.

What is claimed is:

l. A brilliant gem having an axis of symmetry, an upper pyramid section and a lower pyramid section which are located at opposite sides of a girdle plane extending transversely of and through said axis, said upper pyramid section having a table located in a second plane paralleling said girdle plane and an upper plurality of facets which are inclined to said planes, and said lower pyramid section having a lower plurality of facets, each of said pluralities of facets having the same odd number of facet surfaces in excess of nine arranged in form of a ring surrounding said axis and the facets of said lower plurality being inclined to said girdle plane at an angle of between 37 and 45 so that reflected light emerging from said gem through said upper facets is dispersed under a dispersion angle of between 120 and 1257.

2. A brillian gem as defined in claim 1, wherein each facet surface of said lower ring is disposed substantially directly below a facet surface of the upper ring.

3. A brilliant gem as defined in claim 1, wherein the facet surfaces of one of said rings are displaced with reference to the facet surfaces of the other of said rings in circumferential direction of the latter.

A l nt gm @iQifiQQQiQFJQiI .1, where the number of said facet surfaces is (11).

5. A brilliant gem having an axis of symmetry, an upper pyramid section and a lower pyramid section which are located at opposite sides of a girdle plane, said upper pyramid section having a table located in a second plane paralleling said girdle plane and an upper plurality of facets which are inclined to said planes, and said lower pyramid section having a lower plurality of facets, each of said pluralities of facets having the same odd number but not less than I l of facet surfaces arranged in form of a ring surrounding said axis of symmetry, the facets of the ring of the upper pyramid section being circumferentially offset relative to the facets of the ring of the lower pyramid section so that each facet surface of one ring has its center midway between two circumferentially adjacent facet surfaces of the other ring, the facets of said lower plurality being inclined to said girdle plane at an angle of between 37 and 45 so that reflected light emerging from said gem through said upper facets is dispersed under a dispersion angle of between 120 and 1257. 

1. A brilliant gem having an axis of symmetry, an upper pyramid section and a lower pyramid section which are located at opposite sides of a girdle plane extending transversely of and through said axis, said upper pyramid section having a table located in a second plane paralleling said girdle plane and an upper plurality of facets which are inclined to said planes, and said lower pyramid section having a lower plurality of facets, each of said pluralities of facets having the same odd number of facet surfaces in excess of nine arranged in form of a ring surrounding said axis and the facets of said lower plurality being inclined to said girdle plane at an angle of between 37* and 45* so that reflected light emerging from said gem through said upper facets is dispersed under a dispersion angle of between 1*20'' and 12*57''.
 2. A brillian gem as defined in claim 1, wherein each facet surface of said lower ring is disposed substantially directly below a facet surface of the upper ring.
 3. A brilliant gem as defined in claim 1, wherein the facet surfaces of one of said rings are displaced with reference to the facet surfaces of the other of said rings in circumferential direction of the latter.
 4. A brilliant gem as defined in claim 1, wherein the number of said facet surfaces is (11).
 5. A brilliant gem having an axis of symmetry, an upper pyramid section and a lower pyramid section which are located at opposite sides of a girdle plane, said upper pyramid section having a table located in a second plane paralleling said girdle plane and an upper plurality of facets which are inclined to said planes, and said lower pyramid section having a lower plurality of facets, each of said pluralities of facets having the same odd number - but not less than 11 - of facet surfaces arranged in form of a ring surrounding said axis of symmetry, the facets of the ring of the upper pyramid section being circumferentially offset relative to the facets of the ring of the lower pyramid section so that each facet surface of one ring has its center midway between two circumferentially adjacent facet surfaces of the other ring, the facets of said lower plurality being inclined to said girdle plane at an angle of between 37* and 45* so that reflected light emerging from said gem through said upper facets is dispersed under a dispersion angle of between 1*20'' and 12*57''. 